Disk drives typically include a spindle motor for rotating one or more disks in order to read data from and write data to surfaces of the disks. The spindle motor includes a stator having a plurality of coils, and a rotor having one or more rotor magnets and a rotating motor hub on which the disks may be mounted and clamped. Different coils of the stator are alternately energized to form a changing electromagnetic field that pulls/pushes the rotor magnets, thereby rotating the motor hub. Rotation of the motor hub, in turn, results in rotation of the disks mounted thereto.
Conventionally, disks have been mounted and clamped to the motor hub using a disk clamp axially loaded with at least one screw to sandwich the disks between the disk clamp and the motor hub. Relatively high axial loading may be required to keep the disks from slipping. If more than one disk is mounted on the motor hub, the disks may be separated by disk spacers that are positioned between the disks. After mounting the disks to the motor hub, the disk pack assembly (including the disks, disk spacers, disk clamp and screws) must often be carefully biased in order to minimize imbalances arising from off-center mounting of the disks.
Unfortunately, these conventional disk attachment techniques have a number of disadvantages. First, the process of mounting and balancing the disks can be complex and cumbersome. It may be difficult and time-consuming to perfectly balance the disk pack assembly. Second, the high axial loading created by the disk clamp may result in coning of the disks, whereby the outer diameters of the disks are bent out of plane. This coning effect is, of course, undesirable and may even result in servoing errors. Finally, conventional disk attachment can be a significant source of particulate contamination, as the screw tightening process typically yields metallic debris.
There is therefore a need for an improved disk attachment process.